Beyerdynamic DT 990 Pro

I got a 250 ohms Beyerdynamic DT 990 Pro and it sounds nearly the same plugged into my motherboard (ASRock Z270 Pro4 LGA 1151) as it does my 600 ohm sound card (Creative Sound Blaster Audigy FX PCIe). When plugged into my motherboard or sound card they aren't quiet or loud, but if i had to...